Hi Tobias,
mit dem Nadellager hab ich mich tatsächlich geirrt, sorry!
Das frühe Spit Mk3 und das Vitesse/GT6 benutzen tatsächlich das gleiche Nadellager 118507 - press fit.
Das ist allerdings beim Mk3 später geändert worden in 144782 (auch für MkIV). Nur das 1500er ist grösser (13H9513).
Ich dachte immer das das GT6 Getriebe auch das grössere Nadellager hätte.
Der Zahnflankenwinkel und Synchronverzahnung sind irgendwann geändert worden! (siehe unten)
Das die Übersetzung im 4. Gang immer gleich ist, war mir schon klar. Ist ja direkt durchgeschaltet, ohne Zahnräder, 1:1.
Mir ging's um die anderen Übersetzungen. Da spielt das Zahnrad auf der Eingangswelle schon eine Rolle. Ich weiss nicht ob beim Unterschied zum Beispiel des 1. Gangs von 3,746 zu 2,646 nur das "hintere" Zahnradpaar geändert werden muss. Ich kenn leider nicht die Zähneanzahl der jeweiligen Zahnradpaare.
Hier noch ein paar Daten aus Service Bulletins:
Tapered Dog Teeth (Gearbox)- GT-6 Plus and TR-6
May, 1970
GT-6 Plus: Tapered Dog teeth replaced thinned dog teeth on 1st, 2nd, 3rd, and Top speed gears and sleeves at Gearbox # KC 19022.
NOTE: The following new details are not interchangeable with those which the supersede.
QTY NUMBER DESCRIPTION
1 152741 Gear, 1st Speed
1 518312 Sleeve Assembly, Synchro and Operating 1st, 2nd, and reverse gears
1 152743 Gear, 2nd Speed
1 153644 Gear, 3rd Speed (35° Helix)
1 518311 Sleeve Assembly, synchro and operating 3rd and top gears
1 216328 Constants Pinion Shaft (35° Helix)
1 213527 Cluster Gear
TR-6: At gearbox # CD 20282 a similar modification was carried out to the TR-6 gearbox.
NOTE: The following new details are not interechangeable with those which they supersede.
QTY NUMBER DESCRIPTION
1 216393 Mainshaft
1 216245 Mainshaft (Overdrive only)
1 152770 Gear, 1st Speed
1 152771 Gear, 2nd Speed
1 152772 Gear, 3rd Speed
1 216044 Constant Pinion Shaft
1 150989 Needle Roller Bearing
1 142434 Constant Gear
Gear Box 3rd Speed Gear - GT6 & GT6+
August 8, 1969
Your attention is drawn to the variation in the Helix Angle on the 3rd speed gear, gear cluster and constant pinion shaft.
The following part number have a 35° Helix Angle and may be used for all replacements if used as a complete set.
Part Number Description
145994 Gear, 3rd Speed (35° Helix Angle)
213526 Constant Pinion Shaft (35° Helix Angle)
213527 Gear Cluster (35° Helix Angle)
The following part numbers have a 30° Helix Angle and may be used for replacement if used as a complete set.
Part Number Description
132097 Gear, 3rd Speed
Gearbox Selector Rail Modification- Spitfire, GT-6 Plus
June, 1970
At gearbox number FD 55620 and KC 23959, the position of the reverse light switch relative to the selector rail centerline was raised to reduce machining on the reverse rail.
Interchangeability of the top cover as an assembly is not affected, but the reverse selector shaft as a component is not interchangeable owing to a change in the shaft depth for the reverse light plunger.
The latest selector shaft can be fitted to early covers using additional washers under the reverse light switch.
The early type selector shaft in a later cover will not operate the switch.
PART NUMBERS AFFECTED
Spitfire
516080---------------------------------------------------Top Cover Assembly
134290---------------------------------------------------Selector Shaft- Reverse
replaced by
518606---------------------------------------------------Top Cover Assembly
154944---------------------------------------------------Selector Shaft- Reverse
GT-6 Plus
516099---------------------------------------------------Top Cover Assembly
147775---------------------------------------------------Top Cover Sub-assembly
replaced by
518605---------------------------------------------------Top Cover Assembly
154953---------------------------------------------------Top Cover Sub-assembly
154945---------------------------------------------------Selector Shaft- Reverse
mfG
Harry